MY97 日期控件只輸入今天以前的值

<script type="text/javascript">
                        function GetDate() {
                            var date = new Date();
                            return date.toLocaleDateString();
                        }
                    </script>
     @Html.TextBoxFor(m => m.personalInfoModel.CustBirthday, new { @id = "birthDay", @class = "Wdate", @onfocus = "WdatePicker({dateFmt:'yyyy-M-d',minDate:'1900-01-01',maxDate:GetDate()})", style = "width:175px;", @readonly = "readonly" })